This invention relates to rotary machines of the kind comprising:
(a) a casing; PA1 (b) a rotor rotatable eccentrically in, or with one part of, the casing and having means to define with, or with another part of, the casing, peripheral compartments which are separate from each other; PA1 (c) an inlet for the inflow of a medium to the compartments sequentially as the rotor rotates; PA1 (d) an outlet, displaced in the direction of rotation of the rotor from the inlet, for the outflow of said medium, and PA1 (e) a shaft whereby power can be supplied to or taken from said rotor. PA1 (a) a casing; PA1 (b) a rotor rotatable eccentrically in the casing to define an eccentric annulus and having vanes pivotably secured to the periphery of the rotor to define with the casing compartments in the eccentric annulus which are separate from each other; PA1 (c) an inlet opening for the inflow of a medium to the compartments sequentially as the rotor rotates; PA1 (d) an outlet, displaced in the direction of rotation of the rotor from the inlet, for the outflow of said medium; PA1 (e) a coupling whereby power can be supplied to or taken from said rotor; PA1 (f) crank arms movable in planes parallel to but displaced from the planes occupied by the vanes and oscillating arms rotatably oscillatable about a pillar which is fixed in relation to the casing, the oscillating arms being secured to the crank arms to mechanically pivot the crank arms and hence the vanes to their operative positions.
Such machines can be adapted to perform either an engine function by allowing a hot inlet gas to expand in the compartments as the compartments increase in volume or a compressor function by supplying an inlet gas to be compressed in the compartments as the compartments decrease in volume.
Examples of such machines are shown in British Pat. Nos. 355,042; 438,730; 448,903; 453,908; 624,990; 706,292 and 1,540,057. In most of these, the compartments are defined by vanes coupled to the rotor and defining the compartments with the casing, the vanes being in contact with the casing which can give rise to excessive frictional losses. In No. 448,903 the vanes carry a drum in the casing, the drum being driven by the vanes, leading to considerable power requirements.
Further, certain crank-driven vane arrangements require to operate in a casing which is not truly circular and this introduces manufacturing and wear problems.
It is one object of the present invention to provide a crank driven vane arrangement which can operate in a truly circular casing.